Cathodoluminescent gas discharge image display panel

Abstract

This disclosure depicts a high-voltage cathodoluminescent gas discharge image display panel having an ordered array of display elements. The panel includes envelope means containing an ionizable gas at a predetermined very low pressure. The envelope means includes a transparent faceplate on the inner surface of which are disposed cathodoluminescent target elements. Electron source means produces at a given time at least one high-density electron beam, and includes means to cause a plasma sac to generate and gather electrons, and accelerate them to form a concentrated electron beam. An ultor electrode receiving a predetermined relatively high ultor voltage establishes a high voltage gradient in a plasma-free acceleration section which is effective to straight-line accelerate said electron beam in a substantially collision-free path directly into high-energy bombardment of the cathodoluminescent target elements. The panel includes light-stopping means whereby the useful visible light is solely that produced by high-energy electron bombardment of the target elements. Other structures including means for electron beam modulation are disclosed.

I claim: 
     
       1. A very low pressure, high-voltage cathodoluminescent gas discharge image display panel having an ordered array of display elements, the panel including envelope means containing an ionizable gas at a predetermined very low pressure, said envelope means including a transparent faceplate on the inner surface of which are disposed cathodoluminescent target elements associated with said display elements, the panel comprising: electron source means for producing at a given time at least one high-density electron beam, comprising: rearwardly disposed cathode means for receiving a relatively low applied voltage;   grid means located forwardly of said cathode means and including at least an electron-transmissive anode means spaced a predetermined distance from said cathode means for receiving a relatively intermediate applied voltage, and further including a performance enhancement electrode located between said anode means and said cathode means, and co-extensive without interruption across the width and height of said panel, said performance enhancement electrode receiving through a single input terminal a voltage intermediate said relatively intermediate voltage on said anode means and said relatively low voltage on said cathode means, said performance enhancement electrode serving to stabilize said plasma sac in said constriction by conducting electrons from a surrounding area to said sac, thus discouraging the formation of a sac in non-energized neighboring constrictions, said performance enhancement electrode also serving to prime the contained gas in the region of said constriction and thereby permitting a plasma sac to be established in said constriction by application of a lower voltage on said anode means than otherwise possible;     constriction-forming means between said anode means and said cathode means defining a plurality of constrictions each respectively associated with one or more of said display elements, with said intermediate voltage, said predetermined distance, said very low gas pressure, and the individual width of said constrictions having values effective to support a gas discharge plasma between said cathode means and said anode means, and to cause a plasma sac to form in said plasma on the cathode side of said constriction-forming means about the constriction associated with any selected anode means, said plasma sac by its nature generating and gathering electrons from said cathode means and accelerating them into said constriction to form a concentrated electron beam therein;   an ultor electrode disposed contiguous to said cathodoluminescent target elements on said faceplate for receiving a predetermined relatively high ultor voltage, said ultor electrode being separated by a predetermined spacing from said grid means to define an acceleration section therebetween, said spacing being so small that at said predetermined very low pressure and at said ultor voltage, no gas discharge plasma can possibly occur in the acceleration section, said ultor voltage establishing a high-voltage predient in the plasma-free acceleration section which is effective to straight-line accelerate said beam of electrons formed in said constriction in a substantially collision-free path directly into high-energy bombardment of said cathodoluminescent target elements disposed on said faceplate; and   light-stopping means for blocking from view light produced by said plasma, whereby the useful visible light produced by said panel is solely that produced by said high-energy elelctron bombardment of said cathodoluminescent target elements on said faceplate.   
     
     
       2. A very low pressure, high-voltage cathodoluminescent gas discharge image display panel having an ordered array of display elements, the panel including envelope means containing an ionizable gas at a predetermined very low pressure, said envelope means including a transparent faceplate on the inner surface of which are disposed cathodoluminescent target elements associated with said display elements, the panel comprising: electron source means for producing at a given time at least one high-density electron beam, comprising: rearwardly disposed cathode means for receiving a relatively low applied voltage;   grid means located forwardly of said cathode means and including a performance enhancement electrode at a distance D 1  from said cathode means and an anode means at a greater distance D 2  from said cathode means, said anode means being electron-transmissive and receiving a relatively intermediate applied voltage; and   constriction-forming means between said anode means and said performance enhancement electrode and defining at least one constriction registered with a constriction in said performance enhancement electrode, said registered constrictions being respectively associated with one or more of said display elements, with said intermediate voltage, said distance D 2 , said very low pressure, and the width of said registered constrictions having values effective to support a gas discharge plasma between said cathode means and said anode means to cause a plasma sac to form in said plasma about said constriction in said performance enhancement electrode on the cathode side of said barrier means, said plasma sac by its nature generating and gathering electrons from said cathode means and accelerating them into said registered constrictions to form a concentrated electron beam therein, said performance enhancement electrode being co-extensive without interruption across the width and height of the panel and receiving a voltage intermediate said relatively intermediate voltage on said anode means and said relatively low voltage on said cathode means, said performance enhancement electrode serving to stabilize said plasma sac in said registered constrictions   by conducting electrons from a surrounding area to said sac, and at the same time discouraging the formation of a sac in non-energized neighboring display elements, said performance enhancement electrode also serving to prime the contained gas in the region of said constriction and thereby permitting a plasma sac to be supported in said constriction by application of a lower voltage on said anode means than otherwise possible;     an ultor electrode disposed contiguous to said cathodoluminescent material on said faceplate for receiving a predetermined relatively high ultor voltage; that is, a voltage in the range of many hundreds to tens of thousands of volts, said ultor electrode being separated by a predetermined spacing from said grid means to define an acceleration section therebetween, said spacing being so small that at said predetermined very low gas pressure and at said ultor voltage, no gas discharge plasma can possibly occur in the acceleration section, said ultor voltage establishing a high-voltage gradient in the plasma-free acceleration section which is effective to straight-line accelerate said beam of electrons formed in said narrow opening in a substantially collision-free path directly into high-energy bombardment of said cathodoluminescent target elements disposed on said faceplate; and   light-stopping means for blocking from view light produced by said plasma, whereby the useful visible light produced by said panel is solely that produced by said high-energy electron bombardment of said cathodoluminescent target elements on said faceplate.   
     
     
       3. The display panel defined by claim 2 wherein said grid means comprises said anode means and at least one electron-transmissive modulating grid means located down-beam of said anode means for modulating said concentrated electron beam with a time-varying voltage to provide in cooperation with said anode means full control of said electron beam wherein a range of differences in potentials between said anode means and said modulating grid means provides a related range of differences in electron current and thus a related range of differences in luminous output from said cathodoluminescent target elements. 
     
     
       4. A very low pressure, high-voltage cathodoluminescent gas discharge image display panel having an ordered array of display elements, the panel including envelope means containing an ionizable gas at a predetermined very low pressure, said envelope means including a transparent faceplate on the inner surface of which are disposed cathodoluminescent target elements associated with said display elements, the panel comprising: electron source means for producing at a given time at least one high-density electron beam, comprising:   rearwardly disposed cathode means for receiving a relatively low applied voltage;   grid means located forwardly of said cathode means and including a performance enhancement electrode at a distance D 1  from said cathode means and an anode means at a greater distance D 2  from said cathode means, said anode means being electron-transmissive and receiving a relatively intermediate applied voltage, and further including at least one electron-transmissive modulating grid means located down-beam of said anode means for modulating said concentrated electron beam with a time-varying voltage to provide in cooperation with said anode means full control of said electron beam wherein a range of differences in potentials between said anode means and said modulating grid means provides a related range of differences in electron current and thus a related range of differences in luminous output from said cathodoluminescent target elements;   constriction-forming means between said anode means and said performance enhancement electrode and defining at least one constriction registered with a constriction in said performance enhancement electrode, said registered constrictions being respectively associated with one or more of said display elements, with said intermediate voltage, said distance D 2 , said very low pressure, and the width of said registered constrictions having values effective to support a gas discharge plasma between said cathode means and said anode means to cause a plasma sac to form in said plasma about said constriction in said performance enhancement electrode on the cathode side of said barrier means, said plasma sac by its nature generating and gathering electrons from said cathode means and accelerating them into said registered constrictions to form a concentrated electron beam therein, said performance enhancement electrode being co-extensive without interruption across the width and height of the panel and receiving a voltage intermediate said relatively intermediate voltage on said anode means and said relatively low voltage on said cathode means, said performance enhancement electrode serving to stabilize said plasma sac in said registered constrictions by conducting electrons from a surrounding area to said sac, and at the same time discouraging the formation of a sac in non-energized neighboring display elements, said performance enhancement electrode also serving to prime the contained gas in the region of said constriction and thereby permitting a plasma sac to be supported in said constriction by application of a lower voltage on said anode means than otherwise possible;   an ultor electrode disposed contiguous to said cathodoluminescent material on said faceplate for receiving a predetermined relatively high ultor voltage; that is, a voltage in the range of many hundreds to tens of thousands of volts, said ultor electrode being separated by a predetermined spacing from said grid means to define an acceleration section therebetween, said spacing being so small that at said predetermined very low gas pressure and at said ultor voltage, no gas discharge plasma can possibly occur in the acceleration section, said ultor voltage establishing a high-voltage gradient in the plasma-free acceleration section which is effective to straight-line accelerate said beam of electrons formed in said narrow opening in a substantially collision-free path directly into high-energy bombardment of said cathodoluminescent target elements disposed on said faceplate; and   light-stopping means for blocking from view light produced by said plasma, said light-stopping means including a continous, light-reflective film disposed on said cathodoluminescent target elements which is also electrically conductive and serves as said ultor electrode, whereby the useful visible light produced by said panel is solely that produced by said high-energy electron bombardment of said cathodoluminescent target elements on said faceplate.   
     
     
       5. A very low pressure, high-voltage cathodoluminescent gas discharge image display panel having an ordered array of display elements, the panel including envelope means containing a ionizable gas at a predetermined very low pressure, said envelope means including a transparent faceplate on the inner surface of which is disposed cathodoluminescent target elements associated with said display elements, the panel comprising: electron source means for producing at a given time at least one high-density electron beam which is co-extensive with a predetermined group of display elements and which is divided into a plurality of beamlets, one for each element in said group, said electron source means comprising:   rearwardly disposed large-area cathode means for receiving a relatively low applied voltage;   grid means located forwardly of said cathode means and including at least an electron-transmissive anode means co-extensive with said group of elements for receiving a relatively intermediate applied voltage, said grid means including a performance enhancement electrode located between said anode means and said cathode means and coextensive without interruption across the width and height of said panel, said performance enhancement electrode receiving through a single input terminal a voltage intermediate said relatively intermediate voltage on said anode means and said relatively low voltage on said cathode means, said performance enhancement electrode serving to stabilize said plasma sac in said constriction by conducting electrons from a surrounding area to said sac and at the same time discouraging the formation of a sac in non-energized neighboring constrictions, said performance enhancement electrode also serving to prime the contained gas in the region of said constriction and thereby permitting a plasma sac to be established in said constriction by application of a lower voltage on said anode means than otherwise possible;   barrier means between said anode means and said cathode means and defining a narrow constriction associated with said group of display elements, with said intermediate voltage, said predetermined distance, said very low gas pressure, and the individual width of said constriction having values effective to support a gas discharge plasma between said cathode means and said anode means and to cause a plasma sac to form in said plasma on the cathode side of said barrier means about said constriction, said plasma sac by its nature generating and gathering electrons from said plasma and accelerating them into said constriction to form a concentrated electron beam therein;   a plurality of electron-transmissive modulating grids located down-beam of said anode means and respectively associated with said group of elements for effectively dividing said beam into a like plurality of beamlets, and for individually modulating said electron beamlets with a like plurality of time-varying voltages to provide in cooperation with said anode means full control of said electron beamlets wherein a range of differences in potential between said anode means and said modulating grids provides a related range of differences in electron current in each of said beamlets and thus a related range of differences in luminous output from the cathodoluminescent target elements respectively associated with said plurality of display elements; and   an ultor electrode disposed contiguous to said cathodoluminescent target elements on said faceplate for receiving a predetermined relatively high ultor voltage; that is, a voltage in the range of many hundreds to tens of thousands of volts, said ultor anode being separated by a predetermined spacing from said grid means to define an acceleration section therebetween, said spacing being so small that at said predetermined very low pressure and at said ultor voltage, no gas discharge plasma can possibly occur in the acceleration section, said ultor voltage establishing a high-voltage gradient in the plasma-free acceleration section which is effective to straight-line accelerate said beamlets in substantially collision-free paths directly into high-energy bombardment of said cathodoluminescent target elements disposed on said faceplate.   
     
     
       6. A very low pressure, high-voltage cathodoluminescent gas discharge image display panel having a row-and-column array of display elements, the panel including envelope means containing an ionizable gas at a predetermined very low pressure; that is, a fraction of a torr, said envelope means including a transparent faceplate on the inner surface of which are disposed cathodoluminescent target elements associated with said display elements, the panel comprising: electron source means for producing at a given time at least one high-density electron beam, comprising: a rearwardly disposed array of large-area hollow cathodes, each spanning a predetermined plural number of rows and columns, and capable of supplying copious electrons at said predetermined very low pressure, and for receiving a relatively low voltage;   grid means located forwardly of said hollow cathode means and including at least one electron transmissive anode means for receiving a relatively intermediate applied voltage, said grid means further including a performance enhancement electrode located between said anode means and said cathode means, and co-extensive without interruption across the width and height of said panel, said performance enhancement electrode receiving through a single input terminal a voltage intermediate said relatively intermediate voltage on said anode means and said relatively low voltage on said cathode means, said performance enhancement electrode serving to stabilize said plasma sac in said constriction by conducting electrons from neighboring display elements to said sac, and thus discouraging the formation of a plasma sac in non-energized neighboring display elements, said performance enhancement electrode also serving to prime the contained gas in the region of said constriction and thereby permitting a plasma sac to be established in said constriction by application of a lower voltage on said anode means than otherwise possible;   barrier means between said anode means and said cathode means defining a plurality of constrictions each associated with said display elements, with said intermediate voltage, said predetermined distance, said very low gas pressure, and the individual widths of said constrictions having values effective to support a gas discharge plasma between said cathode means and said anode means and to cause a plasma sac to form in said plasma on the cathode side of said barrier means about the constriction associated with any selectively energized anode means, said plasma sac by its nature generating and gathering electrons from a large surrounding area of the associated hollow cathode and accelerating them into said constriction to form a concentrated electron beam therein;     an ultor electrode disposed contiguous to said cathodoluminescent target elements on said faceplate for receiving a predetermined relatively high ultor voltage; that is, a voltage in the range of many hundreds to tens of thousands of volts, said ultor electrode being separated by a predetermined spacing from said grid means to define an acceleration section therebetween, said spacing being so small that at said predetermined very low gas pressure and at said ultor voltage, no gas discharge plasma can possibly occur in the acceleration section, said ultor voltage establishing a high-voltage gradient in the plasma-free acceleration section which is effective to straight-line accelerate said beam of electrons formed in said constriction in a substantially collision-free path directly into high-energy bombardment of said cathodoluminescent target elements disposed on said faceplate; and   light-stopping means for blocking from view light produced by said plasma, whereby the useful visible light produced by said panel is solely that produced by said high-energy electron bombardment of said cathodoluminescent target elements on said faceplate.